Hungry insects threaten food security in a warming climate

As the climate continues to warm, farmers worldwide may experience substantially increased crop losses due to swelling populations of voracious insect pests, particularly in temperate regions where most of the world's grain is grown, researchers suggest. Their new study evaluates the relationships between temperature and insects to predict the impact of growing insect populations on future corn, rice and wheat yields — major staple crops, which combined account for a large portion of the food consumed globally. "Rarely has it been attempted to link temperature responses of pest insects and the damage they cause under warming more widely, and never on a global scale," writes Markus Riegler in a related Perspective. Previous research has shown that an insect's metabolic rate (including rate of food consumption) and population growth, increase with temperature. However, while rising temperatures are likely to reduce global crop yields overall, assessments of the agricultural impacts of climate change rarely account for crop losses due to insects. Here, Curtis Deutsch and colleagues developed a crop yield model that accounted for the biological responses to climate of a variety of insect species, including pests. The model was calibrated using global crop and climate data for several warming scenarios. Its results suggest that global yield losses for the major crops evaluated will increase by 10 to 25% per degree of global surface warming, with the most significant declines occurring in many of the world's most productive agricultural areas, like the United States, France and China. According to Deutsch et al. the findings underscore a need for farmers to prepare for rising insect pressure, which may involve increased use of pesticides despite potential health or environmental damage, to mitigate the impact on the already fragile global food supply.